I hadn't thought about painting interiors of houses as a genre until I painted a picture of the blue Drawing room at Chatsworth. This led to a commission from Prince Charles and thence from one commission to another. An Interior with posed figures is usually referred to as a conversation piece and these are in many ways very similar. I think the difference being that I may add no figures or perhaps just a dog. The focus is on the room.
Rooms are hard to make good compositions out of and that is probably why magazine photographers often move furniture to recompose what they take. People who know the houses in magazines frequently remark that they didn't recognise the house from the photos as they have been so greatly altered.
I prefer to think of the room as a portrait of the people who live there. Any dogs are their dogs and as such should be portraits but they also carry out the useful function of balancing out the spaces and lines within the composition to give a satisfying arrangement.
They are portraits but also a record of the lives of the occupants and how the room stood at the time. People move every few years. One will often think you will always live in the same place, that nothing will ever change, but invariable change come. Finances, health and peoples needs may change and their homes may reflect this. It is all part of moving forward and a record is a often a reassuring reminder of what was.